What is the clean way to do that in C? wchar_t* ltostr(long value) { int size = string_size_of_long(value); wchar_t *wchar_copy = malloc(value * sizeof(wchar_t)); swprintf(wchar_copy, size, L"%li", self); return wchar_copy; } The solutions I came up so far are all rather ugly, especially allocate_properly_size_whar_t uses double float base math.